Lord Śiva, is also called Rudrā, the master of emotions. He is also acknowledged as the Parama-purṣa by Śaiva practitioners. His power is so great that he is called Mahādeva, the great deity who is full of light. This mantra is the Śākhā-gāyatri of Lord Śiva and is recited by his followers daily. Listening to this mantra with an open heart can open your own and allow light to enter your heart.
Listen to it 6 times twice a day. Once at sunrise time and once before sunset.
oṁ tat puruṣāya vidmahe mahādevāya dhīmahi | tanno rudraḥ pracodayāt